1. Field of the Invention
The present invention relates to the field of vehicle steering, and more particularly to a steering transmission mechanism interconnecting front and rear wheels so as to maneuver the vehicle with respect to a longitudinal axis in an arcuate path, a linear path or in a linear angular path.
2. Brief Description of the Prior Art
Maneuverability of a conventional in-line wheeled vehicle, such as a scooter, is limited due to the fact that the front and rear wheels track along a common path that restricts maneuvering. In some instances, maneuverability is increased by permitting rotation or pivoting of the rear wheel to follow the front wheel so that a curvilinear path is followed which allows for more turning freedom and a shorter turning radius. Such examples are disclosed in U.S. Pat. No. 5,954,349, No. 4,799,702, and No. 4,555,122.
However, problems and difficulties have been encountered with these conventional vehicles, which stem largely from the fact that all the interconnecting mechanisms or transmission means between the front and rear wheels are directly connected to and are supported on the vehicle frame. The prior mechanisms rely on cable and pulley arrangements which have a tendency to stretch creating slack or “play” during structural flexing. In other instances, strings, complicated flexible linkages and rider body weight balancing techniques are employed to effect rear wheel pivoting so as to track with the front wheel. Still others, such as disclosed in U.S. Pat. No. 3,620,547 (FIG. 6) permit both turning of the front and rear wheels so as to track along a linear or curvilinear path as well as allowing the wheels to track in parallel in angular relation to the longitudinal axis of the frame wherein such a maneuver gains “crab” maneuvering. Again, it is the shifting of the rider or driver's weight which achieves the pivoting of the rear wheel to effect such maneuvering.
In none of the above reference disclosures is there provision of a mechanism not supported or directly fastened to the frame that employs a rigid mechanism to effect shift or change from turn-steering to crab-steering by manual switch-over control.
Therefore, a long-standing need has existed to provide a steering and transmission assembly for a vehicle, such as an in-line scooter, that is rigidly connected between the front and rear wheels and operable to alternately cause the rear wheel to track the front wheel in a curvilinear path or to cause the rear wheel to pivot parallel to the front wheel where both wheels are in an angular “crab” path with respect to the center line of the vehicle and wherein the assembly is supported on the front and rear wheel assembly without connection or support on the frame of the vehicle.